JavaScript Code
var str = "hi";Memory allocation:
| Address | Value | Description |
|---|---|---|
...... |
... | |
0x1001 |
call object | Start of a call object's memory |
0x1002 |
0x00af | Reference to invoked function |
0x1003 |
1 | Number of references in this call object |
0x1004 |
str | Name of variable (in practice would not be in a single address) |
0x1005 |
0x1001 |
Memory address of "hi" |
...... |
... | |
0x2001 |
string | type identifier |
0x2002 |
2 | number of bytes |
0x2003 |
h | byte of first character |
0x2004 |
i | byte of second character |
When JS runs: var str = "hi"; by calling some function, it first hoists all variable declarations and creates a spot in memory for the variable. This might leave memory something like:
| Address | Value | Description |
|---|---|---|
...... |
... | |
0x1001 |
call object | Start of a call object's memory |
0x1002 |
0x00af | Reference to invoked function |
0x1003 |
1 | Number of references in this call object |
0x1004 |
str | Name of variable |
0x1005 |
empty | |
...... |
... |
In practice, the name of the variable, str, would not be held in a single memory address. Also, the variable names and locations would not be stored in a fixed-memory array (possibly in a hash-table).
Next, the string "hi" would be created in memory like:
| Address | Value | Description |
|---|---|---|
...... |
... | |
0x2001 |
string | type identifier |
0x2002 |
2 | number of bytes |
0x2003 |
h | byte of first character |
0x2004 |
i | byte of second character |
Finally, the pointer address of str would be set to the memory address of "hi" (0x2001), leaving memory as indicated at the top of the page.
i would really appreciate it if someone can help me to check my understanding of this whole process. i wrote them down here, here, and here. Justing wondering coz these things have been bugging me for a while.